交叉分子束方法研究H＋CH4和H＋CD4反应：CH3／CD3的振动激发态产物通道

Crossed Molecular Beam Study of H＋CH4 and H＋CD4 Reactions： Vibrationally Excited CH3/CD3 Product Channels

本文利用时间切片离子成像技术较为系统地研究了H＋CH4／CD4-H2／HD＋CH3／CD3这一反应．通过（2＋1）共振增强多光子电离技术探测了产物CH3／CD3的影像，从中发现该反应在0．72和1．06eV碰撞能下，除了基态产物外，还生成了激发态产物．这一现象并未在前人的实验中观测到．由激发态产物的图像可知，随着碰撞能的增大，产物的角分布逐渐从后向往侧向转移．通过对比产物CH3／CD3的基态与激发态的角分布，可知振动激发态产物更倾向于分布在侧向．由于散射产物的角分布主要受反应碰撞参数的影响，这一实验结果意味着碰撞参数对振动激发态产物通道有着重要的影响．

We study the H＋CH4/CD4-＋H2/HD＋CH3/CD3 reactions using the time sliced velocity map ion imaging technique. Ion images of the CH3/CD3 products were measured by the （2＋1） resonance enhanced multi-photon ionization （REMPI） detection method. Besides the CH3/CD3 products in the ground state, ion images of the vibrationally excited CH3/CD3 products were also observed at two collision energies of 0.72 and 1.06 eV. It is shown that the angular distribution of the products CH3/CD3 in vibrationally excited states gradually vary from backward scattering to sideways scattering as the collision energy increases. Compared to the CH3/CD3 products in the ground state, the CH3/CD3 products in vibrationally excited states tend to be more sideways scattered, indicating that larger impact parameters play a more important role in the vibrationally excited product channels.